Systems and methods for performing simultaneous ablation

ABSTRACT

A system for treating tissue includes first and second ablation devices each including a plurality of wire electrodes and coupled to a generator in parallel. In one embodiment, the generator includes first and second terminals coupled in parallel to one another, and the first and second ablation devices are connected to the first and second terminals, respectively. Alternatively, the first and second ablation devices are coupled to a single terminal of the generator using a “Y” cable. A ground electrode is coupled to the generator opposite the first and second ablation devices for monopolar operation. The first and second arrays of electrodes are inserted into first and second sites adjacent one another within a tissue region. Energy is simultaneously delivered to the first and second arrays to generate lesions at the first and second sites preferably such that the first and second lesions overlap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 10/713,357, filed on Nov. 14, 2003, the disclosures of which ishereby incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention relates to medical devices, and moreparticularly, to systems and methods for ablating or otherwise treatingtissue using electrical energy.

2. Background of the Invention

Tissue may be destroyed, ablated, or otherwise treated using thermalenergy during various therapeutic procedures. Many forms of thermalenergy may be imparted to tissue, such as radio frequency electricalenergy, microwave electromagnetic energy, laser energy, acoustic energy,or thermal conduction.

In particular, radio frequency ablation (RFA) may be used to treatpatients with tissue anomalies, such as liver anomalies and many primarycancers, such as cancers of the stomach, bowel, pancreas, kidney andlung. RFA treatment involves the destroying undesirable cells bygenerating heat through agitation caused by the application ofalternating electrical current (radio frequency energy) through thetissue.

Various RF ablation devices have been suggested for this purpose. Forexample, U.S. Pat. No. 5,855,576 describes an ablation apparatus thatincludes a plurality of wire electrodes deployable from a cannula orcatheter. Each of the wires includes a proximal end that is coupled to agenerator, and a distal end that may project from a distal end of thecannula. The wires are arranged in an array with the distal ends locatedgenerally radially and uniformly spaced apart from the catheter distalend. The wires may be energized in a monopolar or bipolar configurationto heat and necrose tissue within a precisely defined volumetric regionof target tissue. The current may flow between closely spaced wireelectrodes (bipolar mode) or between one or more wire electrodes and alarger, common electrode (monopolar mode) located remotely from thetissue to be heated. To assure that the target tissue is adequatelytreated and/or to limit damaging adjacent healthy tissues, the array ofwires may be arranged uniformly, e.g., substantially evenly andsymmetrically spaced-apart so that heat is generated uniformly withinthe desired target tissue volume. Such devices may be used either inopen surgical settings, in laparoscopic procedures, and/or inpercutaneous interventions.

During tissue ablation, the maximum heating often occurs in the tissueimmediately adjacent the emitting electrodes. In general, the level oftissue heating is proportional to the square of the electrical currentdensity, and the electrical current density in tissue generally fallsrapidly with increasing distance from the electrode. The decrease of acurrent density depends upon a geometry of the electrode. For example,if the electrode has a spherical shape, the current density willgenerally fall as the second power of distance from the electrode. Onthe other hand, if the electrode has an elongate shape (e.g., a wire),the current density will generally fall with distance from theelectrode, and the associated power will fall as the second power ofdistance from the electrode. For the case of spherical electrode, theheating in tissue generally falls as the fourth power of distance fromthe electrode, and the resulting tissue temperature therefore decreasesrapidly as the distance from the electrode increases. This causes alesion to form first around the electrodes, and then to expand intotissue disposed further away from the electrodes.

Due to physical changes within the tissue during the ablation process,the size of the lesion created may be limited. For example, theconcentration of heat adjacent to wires often causes the local tissue todesiccate, thereby reducing its electrical conductivity. As the tissueconductivity decreases, the impedance to current passing from theelectrode to the tissue increases so that more voltage must be suppliedto the electrodes to affect the surrounding, more distant tissue. Thetissue temperature proximate to the electrode may approach 100° C., sothat water within the tissue boils to become water vapor. As thisdesiccation and/or vaporization process continues, the impedance of thelocal tissue may rise to the point where a therapeutic level of currentcan no longer pass through the local tissue into the surrounding tissue.

Thus, the rapid fall-off in current density may limit the volume oftissue that can be treated by the wire electrodes. As such, dependingupon the rate of heating and the size of the wire electrodes, existingablation devices may not be able to create lesions that are relativelylarge in size. Longer wire electrodes and/or larger arrays have beensuggested for creating larger lesions. The effectiveness of suchdevices, however, may be limited by the desiccation and/or vaporizationprocess discussed previously. While wire electrodes can be deployed,activated, retracted, and repositioned sequentially to treat multiplelocations within a tissue region, such an approach may increase thelength of time of a procedure, and precise positioning to ensure that anentire tissue region is treated may be difficult to accomplish.

Accordingly, improved systems and methods for tissue ablation would beuseful.

SUMMARY OF THE INVENTION

The present invention is directed to systems and methods for deliveringenergy to tissue, and more particularly to systems and methods fordelivering energy substantially simultaneously to multiple electrodearrays to increase a volume of tissue being treated.

In accordance with a first aspect of the present invention, a system fortreating tissue within a tissue region is provided that includes asource of energy, a first ablation device including a plurality of wirescoupled to the source of energy, and a second ablation device includinga plurality of wires coupled to the source of energy in parallel withthe first ablation device, whereby the first and second ablation devicescan substantially simultaneously create first and second lesions,respectively, within a tissue region.

In a preferred embodiment, the wires of the first and second ablationdevices are electrodes and the source of energy is a source ofelectrical energy, e.g., a radio frequency (RF) generator. Preferably,the first and second ablation devices include an array of wiresdeployable from a cannula.

The source of electrical energy may include first and second terminalscoupled in parallel to one another. The first ablation device may becoupled to the first terminal and the second ablation device may becoupled to the second terminal. Alternatively, the source of electricalenergy may include a terminal, and a “Y” cable or other connector may becoupled between the first and second ablation devices and the terminalto couple the first and second ablation devices in parallel. Optionally,a ground electrode may be coupled to the source of energy opposite thefirst and second ablation devices, e.g., to provide a return path forelectrical energy delivered to the tissue from the electrodes.

In accordance with another aspect of the present invention, a method isprovided for creating a lesion within a tissue region, e.g., a benign orcancerous tumor within a liver or other tissue structure. A first arrayof electrodes may be inserted into a first site within the tissueregion, and a second array of electrodes may be inserted into a secondsite within the tissue region. Preferably, the second array ofelectrodes is coupled in parallel with the first array of electrodes,e.g., to a RF generator or other source of energy.

In one embodiment, the first and second arrays of electrodes may beintroduced into the first and second sites from first and secondcannulas, respectively. Preferably, the first and second cannulas areintroduced into the tissue region until distal ends of the first andsecond cannulas are disposed adjacent the first and second sites,respectively. The first and second arrays of electrodes may then bedeployed from the distal ends of the first and second cannulas into thefirst and second sites, respectively.

Energy may be substantially simultaneously delivered to the first andsecond arrays of electrodes to generate lesions at the first and secondsites within the tissue region. Preferably, the first and second sitesare disposed adjacent to one another within the tissue region such thatthe first and second lesions at least partially overlap. Optionally, atleast one or both of the first and second arrays of electrodes may beremoved from the tissue region and introduced into a third (and fourth)site within the tissue region, and activated to increase the size of thelesion created. In other embodiments, the first and second arrays ofelectrodes can be placed at different sites, each of which is associatedwith a treatment region. In such arrangement, separate tissues atdifferent treatment sites can be ablated simultaneously.

Other aspects and features of the invention will be evident from readingthe following detailed description of the preferred embodiments, whichare intended to illustrate, not limit, the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the design and utility of preferred embodimentsof the present invention, in which similar elements are referred to bycommon reference numerals. In order to better appreciate how advantagesand objects of the present inventions are obtained, a more particulardescription of the present inventions briefly described above will berendered by reference to specific embodiments thereof, which areillustrated in the accompanying drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are nottherefore to be considered limiting its scope, the invention will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings.

FIG. 1 illustrates a system for delivering electrical energy to tissue,in accordance with a preferred embodiment of the present invention.

FIG. 2 illustrates a variation of the ablation system of FIG. 1, showingthe power supply having a plurality of output terminals.

FIG. 3 is a cross-sectional side view of an embodiment of an ablationdevice, showing electrode wires constrained within a cannula.

FIG. 4 is a cross-sectional side view of the ablation device of FIG. 3,showing the wires deployed from the cannula.

FIGS. 5A-5D are cross-sectional views, showing a method for treatingtissue, in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, in which similar or corresponding partsare identified with the same reference numeral, FIG. 1 shows a preferredembodiment of an ablation system 10, in accordance with the presentinvention. The ablation system 10 includes a source of energy 12, e.g.,a radio frequency (RF) generator, having an output terminal 14, aconnector 16, a first ablation device 18, and a second ablation device20. One or both of the first and the second ablation devices 18, 20 maybe capable of being coupled to the generator 12.

The generator 12 is preferably capable of operating with a fixed orcontrolled voltage so that power and current diminish as impedance ofthe tissue being ablated increases. Exemplary generators are describedin U.S. Pat. No. 6,080,149, the disclosure of which is expresslyincorporated by reference herein. The preferred generator 12 may operateat relatively low fixed voltages, typically below one hundred fiftyvolts (150 V) peak-to-peak, and preferably between about fifty and onehundred volts (50-100 V). Such radio frequency generators are availablefrom Boston Scientific Corporation, assignee of the present application,as well as from other commercial suppliers. It should be noted that thegenerator 12 is not limited to those that operate at the range ofvoltages discussed previously, and that generators capable of operatingat other ranges of voltages may also be used.

The connector 16 includes an input terminal 22, a first output terminal24, and a second output terminal 26 that is connected in parallel withthe first output terminal 24. The first and second output terminals 24and 26 of the connector 16 are configured for coupling to the first andsecond ablation devices 18, 20, respectively, while the input terminal22 of the connector 16 is configured for coupling to the output terminal14 of the generator 12. Optionally, the ablation system 10 may includeone or more cables 28, e.g., extension cables or cables that extend fromthe first and second ablation devices 18, 20. If cables 28 are notprovided, the first and second ablation devices 18, 20 may be coupleddirectly to the output terminals 24 and 26, respectively, of theconnector 16. In the illustrated embodiment, the connector 16 maydeliver power from the generator 12 simultaneously to the first andsecond ablation devices 18, 20. If it is desired to deliver power tomore than two ablation devices, the connector 16 may have more than twooutput terminals connected in parallel to one another (not shown).

Alternatively, as shown in FIG. 2, instead of the “Y” connector 16, agenerator 12′ may be provided that includes two (or optionally more)output terminals 14′ coupled in parallel with one another. In this case,first and second ablation devices 18,′ 20′ may be coupled to separateoutput terminals 14′ of the generator 12′ without requiring a connector16 (not shown, see FIG. 1). However, if the generator 12′ does notprovide an adequate number of output terminals 14 for the number ofablation devices desired, one or more connectors 16 (not shown) may beused to couple two or more ablation devices to a single output terminalof the generator 12.′

The output terminals 14′ of the generator 12′ may be coupled to commoncontrol circuits (not shown) within the generator 12.′ Alternatively,the generator 12′ may include separate control circuits coupled to eachof the output terminals 14.′ The control circuits may be connected inparallel with one another, yet may include separate impedance feedbackto control energy delivery to the respective output terminals 14.′ Thus,the output terminals 14′ may be connected in parallel to an activeterminal of the generator 12′ such that the ablation devices 18,′ 20′deliver energy to a common ground pad electrode (not shown) in amonopolar mode. Alternatively, the output terminals 14′ may be connectedto opposite terminals of the generator 12′ for delivering energy betweenthe ablation devices 18,′ 20′ in a bipolar mode.

Turning to FIGS. 3 and 4, in a preferred embodiment, each of theablation devices 18, 20 of FIG. 1 (or alternatively, the ablationdevices 18,′ 20′ of FIG. 2) may be a probe assembly 50. The probeassembly 50 may include a cannula 52 having a lumen 54, a shaft 56having a proximal end 58 and a distal end 60, and a plurality ofelectrode wires 62 secured to the distal end 60 of the shaft 56. Theproximal end 58 of the shaft 56 may include a connector 63 for couplingto the generator 12. For example, the connector 62 may be used toconnect the probe assembly 50 to a cable 66, which may be part of theconnector 16 (not shown, see FIG. 1), an extension cable, or a cablethat extends from the output terminal 14 of the generator 12.Alternatively, the probe assembly 50 may itself include a cable (notshown) on the proximal end 58 of the shaft 56, and a connector may beprovided on the proximal end of the cable (not shown).

The cannula 52 may have a length between about five and thirtycentimeters (5-30 cm), and/or an outer diameter or cross sectionaldimension between about one and five millimeters (1-5 mm). However, thecannula 52 may also have other lengths and outer cross sectionaldimensions, depending upon the application. The cannula 52 may be formedfrom metal, plastic, and the like, and/or may be electrically active orinactive within the probe assembly 50, depending upon the manner inwhich electrical energy is to be applied.

The cannula 52 may coaxially surround the shaft 56 such that the shaft56 may be advanced axially from or retracted axially into the lumen 54of the cannula 52. Optionally, a handle 64 may be provided on theproximal end 58 of the shaft 56 to facilitate manipulating the shaft 56.The wires 62 may be compressed into a low profile when disposed withinthe lumen 54 of the cannula 52, as shown in FIG. 3. As shown in FIG. 4,the proximal end 58 of the shaft 56 or the handle 64 (if one isprovided) may be advanced to deploy the wires from the lumen 54 of thecannula 52. When the wires 62 are unconfined outside the lumen 54 of thecannula 52, they may assume a relaxed expanded configuration. FIG. 4shows an exemplary two-wire array including wires 62 biased towards agenerally “U” shape and substantially uniformly separated from oneanother about a longitudinal axis of the shaft 56. Alternatively, eachwire 62 may have other shapes, such as a “J” shape, and/or the array mayhave one wire 62 or more than two wires 62. The array may also havenon-uniform spacing to produce an asymmetrical lesion. The wires 62 arepreferably formed from spring wire, superelastic material, or othermaterial, such as Nitinol, that may retain a shape memory. During use ofthe probe assembly 50, the wires 62 may be deployed into a target tissueregion to deliver energy to the tissue to create a lesion.

Optionally, a marker (not shown) may be placed on the handle 64 and/oron the proximal end 58 of the shaft 56 for indicating a rotationalorientation of the shaft 56 during use. The probe assembly 50 may alsocarry one or more radio-opaque markers (not shown) to assist positioningthe probe assembly 50 during a procedure, as is known in the art.Optionally, the probe assembly 50 may also include a sensor, e.g., atemperature sensor and/or an impedance sensor (not shown), carried bythe distal end of the shaft 56 and/or one or more of the wires 62.

Exemplary ablation devices having a spreading array of wires have beendescribed in U.S. Pat. No. 5,855,576, the disclosure of which isexpressly incorporated by reference herein.

It should be noted that the ablation devices 18, 20 are not necessarilylimited to the probe assembly 50 shown in FIGS. 3 and 4, and that eitheror both of the ablation devices 18, 20 may be selected from a variety ofdevices that are capable of delivering ablation energy. For example,medical devices may also be used that are configured for deliveringultrasound energy, microwave energy, and/or other forms of energy forthe purpose of ablation, which are well known in the art. Furthermore,the first and second ablation devices 18, 20 are not necessarily limitedto the same type of devices. For example, the first ablation device 18may deliver ultrasound energy while the second ablation device 20 maydeliver radio-frequency energy. Also, the first and second ablationdevices 18, 20 may have different sizes of arrays of wires 62, and/ordifferent types or numbers of electrodes. For example, either of thefirst and second ablation devices 18, 20 may be an elongate membercarrying a single electrode tip.

Referring now to FIGS. 5A-5D, the ablation system 10 may be used totreat a treatment region TR within tissue located beneath skin or anorgan surface S of a patient. The tissue TR before treatment is shown inFIG. 5A. As shown in FIG. 5B, the cannulas 52 of the first and secondablation devices 18, 20 may be introduced into the treatment region TR,so that the respective distal ends of the cannulas 52 of the first andsecond ablation devices 18, 20 are located at first and second targetsites TS1, TS2. This may be accomplished using any of a variety oftechniques. In some cases, the cannulas 52 and shafts 56 of therespective ablation devices 18, 20 may be introduced into the targetsite TS percutaneously, i.e., directly through the patient's skin, orthrough an open surgical incision. In this case, the cannulas 52 mayhave a sharpened tip, e.g., a beveled or pointed tip, to facilitateintroduction into the treatment region. In such cases, it is desirablethat the cannulas 52 be sufficiently rigid, i.e., have sufficient columnstrength, so that the cannulas 52 may be accurately advanced throughtissue.

In an alternative embodiment, the cannulas 52 may be introduced withoutthe shafts 56 using internal stylets (not shown). Once the cannulas 52are positioned as desired, the stylets may be exchanged for the shafts56 that carry the wires 62. In this case, each of the cannulas 52 may besubstantially flexible or semi-rigid, since the initial column strengthof the apparatus 10 may be provided by the stylets. Various methodsknown in the art may be utilized to position the probe 50 beforedeploying the wires.

In a further alternative, one or more components or elements may beprovided for introducing each of the cannulas 52 to the treatmentregion. For example, a conventional sheath and sharpened obturator(stylet) assembly (not shown) may be used to access the target site(s).The assembly may be positioned using ultrasonic or other conventionalimaging. Once properly positioned, the obturator/stylet may be removed,providing an access lumen through the sheath. The cannula 52 and shaft56 of each of the ablation devices 18, 20 may then be introduced throughthe respective sheath lumens so that the distal ends of the cannulas 52of the first and second ablation devices 18, 20 advance from the sheathsinto the target sites TS1, TS2.

Turning to FIG. 5C, after the cannulas 52 of the ablation devices 18, 20are properly placed, the shafts 56 of the respective ablation devices18, 20 may be advanced distally, thereby deploying the arrays of wires62 from the distal ends of the respective cannulas 52 into the targetsites TS1, TS2. Preferably, the wires 62 are biased to curve radiallyoutwardly as they are deployed from the cannulas 52. The shaft 56 ofeach of the ablation devices 18, 20 may be advanced sufficiently suchthat the wires 62 fully deploy to circumscribe substantially tissuewithin the target sites TS1, TS2 of the treatment region TR, as shown inFIG. 5D. Alternatively, the wires 62 may be only partially deployed ordeployed incrementally in stages during a procedure.

If the generator 12 of the ablation system 10 includes only one outputterminal 14, one or more connectors 16, described previously, may beused to couple the ablation devices 18, 20 to the output terminal 14. Ifthe generator 12 includes more than one output terminals 14, theablation devices 18, 20 may be coupled directly to the generator 12without using the connector 16. Extension cables 28 may also be used tocouple the ablation devices 18, 20 to the connector 16 or to thegenerator 12. The ablation devices 18, 20 may be coupled to thegenerator 12 in parallel with one another after the wires 62 of therespective ablation devices 18, 20 have been deployed. Alternatively,the wires 62 may be coupled to the generator 12 before the cannulas 52are introduced to the treatment region, or at any time before the tissueis ablated. A neutral or ground electrode, e.g., an external electrodepad, may be coupled to the opposite terminal (not shown) of thegenerator 12 and coupled to the patient, e.g., the patient's skin, in aconventional manner.

Next, energy, preferably RF electrical energy, may be delivered from thegenerator 12 to the wires 62 of the respective ablation devices 18, 20,thereby substantially simultaneously creating lesions at the first andsecond target sites TS1, TS2 of the treatment region TR, respectively.Because the ablation devices 18, 20 are connected in parallel to thegenerator 12, as the impedance of tissue at one of the target sites TS1,TS2 increases, e.g., as the tissue is desiccated or otherwise treated,current may continue to flow to the other target site(s) to completetreatment of both target sites.

Simultaneously creating two or more lesions within a treatment regionmay substantially reduce the duration of an ablation procedure. Inaddition, using only a single generator 12 (or fewer generators thandeployed ablation devices) may reduce the cost of equipment necessary tocomplete a procedure. When desired lesions at the first and secondtarget sites TS1, TS2 of the treatment region TR have been created, thewires 62 of each of the ablation devices 18, 20 may be retracted intothe respective lumens 54 of the cannulas 52, and the ablation devices18, 20 may be removed from the treatment region TR. In many cases, twoablation devices 18, 20 may be sufficient to create a desired lesion.However, if it is desired to perform further ablation to increase thelesion size or to create lesions at different site(s) within thetreatment region TR or elsewhere, the wires 62 of either or both of theablation devices 18, 20 may be introduced and deployed at differenttarget site(s), and the same steps discussed previously may be repeated.

Although an embodiment has been described with reference to placingablation devices at different sites that are within a treatment region,the scope of the invention should not be so limited. In alternativeembodiments, the ablation devices 18, 20 are disposed at differentsites, each of which is associated with a treatment region. In sucharrangement, separate tissues at different sites can be ablatedsimultaneously. In addition, it should be noted that the scope of theinvention should not be limited to the ablation system 10 having twoablation devices. In alternative embodiments, the ablation system 10 canhave more than two ablation devices.

Thus, although several preferred embodiments have been shown anddescribed, it would be apparent to those skilled in the art that manychanges and modifications may be made thereunto without the departingfrom the scope of the invention, which is defined by the followingclaims and their equivalents.

1-42. (canceled)
 43. A system for treating tissue within a tissue regionusing two different energy types, comprising: a first ablation devicecomprising a first structure configured to deliver energy of a firsttype; a second ablation device comprising a second structure configuredto delivery energy of a second type different from the first type,wherein the first ablation device and the second ablation device areconfigured for creating first and second lesions at first and secondsites, respectively, within the tissue region, and wherein the firststructure and the second structure are independently moveable relativeto each other.
 44. The system of claim 43, wherein the first ablationdevice is configured to delivery ultrasound energy while the secondablation device is configured to delivery radio frequency energy. 45.The system of claim 44, wherein the second ablation device comprises anelongate member carrying at least one electrode.
 46. The system of claim45, wherein the at least one electrode comprises a single electrodedisposed at a distal tip of the elongate member.
 47. The system of claim45, wherein the at least one electrode comprises a plurality ofelectrodes disposed at a distal tip of the elongate member.
 48. Thesystem of claim 47, wherein the plurality of electrodes comprise wires.49. The system of claim 44, further comprising a source of ultrasoundenergy operatively coupled to the first ablation device.
 50. The systemof claim 44, further comprising a source of electrical energyoperatively coupled to the second ablation device.
 51. The system ofclaim 50, wherein the source of electrical energy comprises a radiofrequency (RF) generator.
 52. The system of claim 44, wherein the firststructure and the second structure are laterally moveable relative toeach other.
 53. The system of claim 44, wherein the first structurecomprises a cannula having a lumen and a shaft disposed within thelumen.
 54. The system of claim 44, wherein the second structurecomprises a cannula having a lumen and a shaft disposed within thelumen.
 55. The system of claim 44, wherein the first ablation device andthe second ablation device are configured for creating first and secondlesions substantially simultaneously.
 56. A method for creating a lesionwithin a tissue region, the method comprising: inserting a firstablation device configured to deliver energy of a first type into afirst site within the tissue region; inserting a second ablation deviceconfigured to deliver energy of a second type into a second site withinthe tissue region, wherein the first ablation device and the secondablation device are independently moveable relative to each other; anddelivering energy from the first ablation device and the second ablationdevice to generate lesions at the first and second sites within thetissue region.
 57. The method of claim 56, wherein the first ablationdevice and the second ablation are laterally moveable relative to eachother.
 58. The method of claim 56, wherein the first ablation device isconfigured to delivery ultrasound energy while the second ablationdevice is configured to delivery radio frequency energy.
 59. The methodof claim 56, wherein the first ablation device and the second ablationdevice are configured for percutaneous introduction into the tissueregion.
 60. The method of claim 56, wherein the tissue region comprisesa liver.
 61. The method of claim 56, wherein the lesions at the firstand second site at least partially overlap.
 62. The method of claim 56,wherein insertion of the first ablation device comprises inserting acannula having a lumen into tissue and inserting a shaft into the firstsite within the tissue region.
 63. The method of claim 56, whereininsertion of the second ablation device comprises inserting a cannulahaving a lumen into tissue and inserting a shaft into the second sitewithin the tissue region.
 64. The method of claim 56, wherein the energyfrom the first ablation device and the second ablation device aredelivered substantially simultaneously.
 65. A system for treating tissuewithin a tissue region using two different energy types, comprising: afirst ablation device having at least one electrode configured todeliver radio frequency energy; a second ablation device configured todelivery ultrasound energy, wherein the first ablation device and thesecond ablation device are configured for creating first and secondlesions at first and second sites, respectively, within the tissueregion, and wherein the first structure and the second structure areindependently moveable relative to each other; and a source ofelectrical energy operatively coupled to the at least one electrode. 66.The system of claim 65, wherein the first ablation device and the secondablation device are configured for creating first and second lesionssubstantially simultaneously.